# NTSB CHI93IA060: Beech B90, N31SV, Sioux Falls, SD, December 29, 1992

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: December 29, 1992, 03:50 local (09:50 UTC)
- Place: Sioux Falls, SD
- Coordinates: 43.550834, -96.689079 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=43.5508&lon=-96.6891&mi=10
- Phase of flight: [Standing](https://openairdocs.org/ntsb-phases/150) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 3 uninjured
- Status: Completed, report September 28, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 15591
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI93IA060
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/15591/pdf
- Page: https://openairdocs.org/ntsb/CHI93IA060

## Probable cause

THE PILOT-IN-COMMAND'S INADEQUATE PREFLIGHT.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Airframe/component/system failure/malfunction, standing - pre-flight
  - annunciator panel light(s) - failure,partial (contributing factor)
  - door,entrance stair - unlatched (contributing factor)
  - aircraft preflight - inadequate, pilot in command (cause)
- Airframe/component/system failure/malfunction, cruise - normal
  - door,entrance stair - separation

## Analysis

THE NIGHT POSITIONING FLIGHT WAS IN CRUISE FLIGHT AT 14,000 FEET WHEN THE MAIN CABIN DOOR SEPARATED FROM THE AIRPLANE.  AN EXAMINATION OF THE DOOR REVEALED THAT THE DOOR LATCH MECHANISM WAS CAPABLE OF PROPER OPERATION WHEN SECURED PROPERLY.  AN EXAMINATION OF THE ANNUNCIATOR DOOR WARNING LIGHT SYSTEM REVEALED THAT WHEN THE DIMMING RHEOSTAT WAS FULL DIM, THE 'DOOR OPEN' LIGHT WENT OUT.  ONE OF THE TWO BULBS WAS BURNT OUT.

## Aircraft

- Registration: N31SV (not matched to a registry record)
- Reported make and model: BEECH B90
- Category: Airplane
- Serial number: LJ362
- Airframe hours: 8098
- Engines: P&W PT6-20 550 horsepower turbo prop
- Damage: Minor damage
- Flight: Positioning, Part 91
- Operator: Sioux Valley Hospital Assn.
- Registered owner: Sioux Valley Hospital Assn.
- Airworthiness certificate: Standard, Normal
- Last inspection: AAIP, June 9, 1992, 63 hours before
- Destination: 0V6, MISSION, SD
- Flight plan: IFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 34; flight instructor, commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; seat: left; flight hours: 3,135 total, 835 in this make and model, 2,625 as pilot in command, 195 in the last 90 days, 52 in the last 30 days, 5 in the last 24 hours

## Weather

- Conditions: Instrument (IMC), Night/dark
- Wind: 360° at 12 knots
- Visibility: 1 statute miles
- Lowest ceiling: 1,000 ft overcast
- Temperature: 1 °F, dew point -0 °F
- Altimeter: 30.00 inHg
- Observed at: FSD, 40 nm away

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Incident 19921229054899I](https://openairdocs.org/incident/19921229054899I), Dec 29, 1992: Beech B90, Sioux Falls, SD, Minor damage. Cabin door opened inflight and departed aircraft. Cause unknown. Annuciator cabin door open light bulb burned out.

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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